1. Field of the Invention
The present invention relates to a method and apparatus for bonding a film to a substrate. The present invention particularly relates to the bonding of a laminated film consisting of a photosensitive resin layer and a light-transmissible resin film, under pressure, to a base plate for a printed circuit board.
2. Description of the Background Art
When a continuous laminated film is bonded to a base plate for a printed circuit board by a conventional apparatus, the film must be cut to a length corresponding to that of the base plate. The cutting operation is conducted as the base plate is being conveyed by a roller conveyor or the like. The cutoff of the film is performed by a moving cutoff unit which forms a part of the conventional apparatus. The cutoff unit has a rotary cutting disk which is drawn reciprocally across the width of the film.
The laminated film being continuously fed onto the surface of the base plate, as the plate is being moved, should be cut exactly perpendicularly to the longitudinal direction of the film. To accomplish this, the rotary cutting disk of the moving cutoff unit of the conventional apparatus must be reciprocated very quickly. Since the width of the laminated film may exceed 820 mm, the rotary cutting disk must be moved by a length of about 900 mm. The speed of the cutoff unit is such that it takes a least about 0.7 second to move the cutoff unit across a film of 820 mm in width. For that reason, the speed of the feed of the laminated film can be only set at about 4 m/min. or less. This low speed is undesirable in a high speed manufacturing operation. Furthermore, the quick movement and stoppage of the rotary cutting disk will impart strong forces on the guide members for the disk. These forces tend to stress the guides and make the maintenance cost of the apparatus high.
Accordingly, it is an object of the present invention to provide a method in which a continuously fed film, having a large width, may be accurately and quickly cut off perpendicularly to the direction of the feed of the film by a rotary disk cutter, without causing undesired droop of the film, and then bonded to a substrate.
It is another object of the present invention to provide an apparatus by which the continuously fed film, having a large width, may accurately and quickly cut off perpendicularly to the direction of the feed of the film through the use of the rotary cutter, without causing undesired droop of the film, and then bonded to the substrate.
It is yet another object of the present invention to provide a technique for cutting off a portion of a continuous film in such a manner as to prevent strong forces from being imparted to a guide member for the cutter.
The above-mentioned and other objects of the present invention and the novel features thereof will be apparent from the description herein and the drawings attached hereto.